It was very likely due to the debugging I did during the testing, the error should not occur again. Let me know if it does by any chance, luckily it does not look anything serious, it only reports one specific hook not firing in time.
I will keep this topic open for a while, in case the error comes back.
If you like the plugin and have not rated already, feel free to leave a rating on your codecanyon downloads page and on the wordpress plugin repository, it’s greatly appreciated.